1. Field of the Invention
The present invention relates to a dynamic memory using metal oxide semiconductor field effect transistors (MOSFET's).
2. Description of the Prior Art
A dynamic memory device of the single element type is not well-known. In such a memory, since each storage cell is composed of one FET and one capacitor, the size of each cell can be made very small. As the capacity of the memory increases, the size of each storage cell must decrease when overall dimensions are fixed. Therefore, the pitch (or the amount of space for each column) of the storage cells in a large capacity dynamic memory is small, making it difficult to place a sense amplifier, which has a complicated construction, at the end of each column of cells.
In a known dynamic memory device of the single element type, sense amplifiers are disposed on both sides of the storage cell array at one pitch intervals. In other words, in this prior art dynamic memory, sense amplifiers for accessing adjacent column lines are disposed on opposite sides of the storage cell array. According to this prior art device, twice the usual pitch space is available for each of the sense amplifiers, enabling the pitch to be further narrowed. However, a column decoder with an input/output (I/O) circuit must be provided on each side of the storage cell array. These column decoders occupy a large area of the device. Furthermore, the decoders require long address lines for connection thereto, and the load of the address lines becomes large. This makes it extremely difficult to layout the address lines and greatly decreases the access speed.